Process of dyeing keratinous fibers



Unite States Patent 07 3,075,821 PROCESS OF DYEING KERATINOUS FIBERS Robert L. Goldemherg, Haworth, and Robert J. James, Metuchan, N.J., assignors to Shulton, Inc., Clifton, N .J., a corporation of New Jersey No Drawing. Filed Aug. 18, 1960, Ser. No. 50,323 7 Claims. (Cl. 810) This invention relates to the dyeing of keratinous fibers, such as human hair, animal hair, furs, feathers, wool, including individual fibers and fibers in the form of yarns, or knitted, woven or felted fabrics.

The dyeing of keratinous fibers presents difficult and special problems to obtain satisfactory penetration of the dye solution and dyeings reasonably fast to washing, such, for example, as shampooing or laundering.

The present invention provides a method of dyeing keratinous fibers as such or in the form of yarns or fabrics which results in thedesired shades, reasonably fast to washing.

It is among the objects of the present invention to provide a novel process for dyeing keratinous fibers, resulting in dyeings of desired shade, reasonably fast to washing as, for example, shampooing.

It is another object of this invention to provide such process in which relatively minute amounts of the dye or color-forming constituents need be used thus resulting in color formation without materially affecting the feel or hand of the fibers. The amount, if desired, may be so small that it is indeed surprising that with such small amount of color-forming material the desired coloration is obtained.

It is still another object of the present invention to provide such process which is applicable to the dyeing of bleached or unbleached keratinous fibers and results in the desired dyeing of a character such that the dye is reasonably and adequately fast to a washing and yet can be removed by suitable treatment without injury to the keratinous fibers.

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

In accordance with this invention, the keratinous fibers, including wool and silk, to be dyed whether in the form of individual fibers, filaments, yarns or fabrics are subjected to treatment first with a mordanting composition comprising an aqueous solution of a metal salt, the metal ion of which is cobalt, nickel, copper, zinc, palladium, silver, cadmium, or a mixture of two or more of these metals, and thereafter with a solution of a dithio-oxamide or of a mixture of dithiooxamides (including slurries).

The solution containing the metal ion should contain some Water. Preferably, an aqueous solution of a metal salt which is soluble in water is used. Metal salts sparingly soluble in water are useful in the practice of this invention. Preferred salts are the sulfates, nitrates, phosphates, acetates, chlorides, and citrates of the enumerated metals. As the anion of the metal salt has little or no effect on the color formation, it will be appreciated that the invention is not limited to the enumerated salts but includes other salts of cobalt, nickel, copper, zinc, palladium, silver and cadmium, which are soluble, including sparingly soluble salts, in the solvent medium.

While water is the preferred solvent, the invention contemplates the use of co-solvents, such as ethanol, acetone, isopropanol, Carhitols (diethylene glycol monoethyl ether), Cellosolves (ethoxy alkanols), glycols especially the higher glycols such as hexylene glycol, along with the water, particularly when using metal salts which are sparingly soluble, or substantially insoluble in water 3,075,821 Patented Jan- 29, 1963 ICC alone, but have appreciable solubility in the water cosolvent system.

The concentration of the metal ion in the solution containing it should be at least 0.00002 Molar. More concentrated solutions, saturated solutions, and even slurries of the metal salt can be used, although a slurry would be wasteful of the metal ion. The concentration of the metal ion controls the rate at which metal ion will deposit; the final color intensity increases as the ion concentration increases for any given period of immersion time. Accordingly, highly concentrated solutions should be used with markedly less immersion times than dilute solutions to obtain substantially the same color intensity. A feature of this invention is that solutions containing as little as 0.00002 Molar of metal ion for a period of immersion of about five minutes give intense colors upon treatment with a solution of a dithio-oxamide or of a mixture of dithio-oxamides, as hereinafter disclosed, the latter solution having a concentration as low as 0.00002 Molar of the dithio-oxamide or of the mixture of dithiooxamides. Accordingly, the utilization, of relatively minute amounts of the color-producing constituents results in the production of the desired color on the fiber subjected to treatment. This feature is particularly advantageous in the dyeing of human or animal hair, leather and furs, because the desired color is obtained without affecting detrimentally the hand or feel of these fibers and without hazard to the skin or hide.

The cation of the metal salt is one important factor controlling the color obtained. The color is dependent not only upon the cation of the metal salt, but the fiber treated and the particular dithio-oxamide utilized. The anion of the metal salt has little or no effect upon the color obtained except as the anion controls the solubility of the salt. Metal salts, which are sparingly soluble, produce colors of lower intensity than those which are readily soluble in water.

Cobalt salts produce colors which range from light golden yellow to deep red oranges. Thus, for example, cobalt salts with dithio-oxamide produce red orange colors. Nickel salts produce light yellows, orange hues, rose hues, purples, and intense blues, dependent upon the dithio-oxamide employed. Thus, for example, nickel sulfate with dithio-oxamide produces blue, nickel sulfate with N,N methyl dithio-oxamide produces a rose color.

Copper salts result in deep green, olive green, and chocolate brown shades. Thus, for example, copper with N,N di-allyl dithio-oxamide produces green. Zinc salts with practically all of the dithio-oxamides give weak yellow shades. Zinc salts are particularly useful in combination with the other metals to modify the shade pro duced by such other metal.

Palladium salts produce intense yellows, and this is the case with practically all of the dithio-oxamides. Silver salts produce chocolate brown shades withpractically all dithio-oxamides. Cadmium salts, like zinc, produce yel low shades; cadmium is also useful in conjunction with the other metals to modify the colors obtained by such other metals. i

The pH of the solution of the metal salt is an important factor in controlling the color obtained, particu: larly the intensity of the color. In general, the pH of the metal salt solution when applied to the fiber, should be within the range of from 2 to 11. Best results are obtained with nickel salt solutions at a pH within the range of from 6 to 10; with copper salt solutions at a pHwithin the range of 4 to 6; and with cobalt salt solutions at a pH within the range of from 6 to 10. I

' The desired pH may be produced by forming the Ammonia Methylamine Butylamine Octylamine Ethylene diamine 1,6-hexanediamine Methane diamine Aminoethanolamine N(1,1 dimethyl 2 hydroxyethyl)2-methyl-l,2-propanediamine N phenyl 2- methyl 1,2-propanediamine Monohydroxy ethyltrihydroxy propyl ethylene diamine Diethylene triamine Triethylene tetramine Tetraethylene pentamine Hexamethylene tetramine 3-methoxy propylamine 3-isopropoxy propylamine 3-dimethylarnino ptopylamine 3,3-imino bispropylamine 3-di N butylamine propylamine Diethylamine Di N butylamine Diisopropylamine Di Z-ethylhexylarnine Diethanolamine Triethanolamine Dimethylethanolamine Triethylamine Morpholine Glycine Sarcosiue 2-amino l-butanol Z-amino Z-methyl 1,3-propanediol Z-amino Z-methyl l-propanol Hydrazine hydrate Sodium hydroxide Potassium hydroxide in the temperature of 25 C.v increases the rate of ad- 7 dylalkyl, phenylalkyl, phenylpyridyl, chlorophenyl, allyl, benzyl, furfuryl and pyridyl radicals. The alkyl radical whether alone or combined can contain up to 20 carbon atoms. In the case of the carboxyalkyl and sulfoalkyl dithio-oxamides, not only these substituted dithiooxamides can be used but also the ammonium, alkali metal, preferably sodium or potassium and alkaline earth metal, particularly calcium or magnesium can be used. The expression a dithio-oxamide is used herein to include not only dithio-oxamide, but its derivatives herein identified. Examples of dithio-oxamides which have been found useful are:

N,N-dimethyldithio-oxamide N,N'-diethyldithio-oxamide N,N-dipropyldithio-oxamide N,N'-diisopropyldithio-oxamide N,N-dipentyldithio-oxamide N,N'-dioctadecyldithio-oxamide N,N'-di-nonadecyldithio-oxamide N,N'-bis(3-methoxypropyl) dithio-oxamide N,N'-bis(3-hexylundecyl) dithio-oxamide N,N-bis(l-carboxyethyl) dithio-oxamide N,N'-bis'(3-carboxypropyl) dithio-oxamide N,N'-bis(5-carboxyamyl) dithio-oxamide N,N'-dial1yldithio-oxamide N,N'-bis(2-sulfoethyl) dithio-oxamide, disodium salt N,N'-bis(2-sulfoethyl) dithio-oxamide, dicalcium salt N,N'-difurfuryldithio-oxamide N,N-bis(dimethylaminoethyl) dithio-oxamide N,N'-bis(3-dimethylaminopropyl) dithio-oxamide N,N-bis(2-acetoxyethyl) dithio-oxamide N,N'-bis(2-hydroxypropy1-1) dithio-oxamide Two or more of the dithio-oxamides may be dissolved in the same solution and the resultant solution applied to V the fiber.

. o The colors produced are specific to the particular fiber sorption by a factor of about 8. Thus, colors prepared with the metal ion solution at C. are usually 8 times more intense than those prepared With a solution at 25 C. for the same relatively short time of treatment, provided the metal ion adsorption at the lower temperature has not reached a level such that complete saturation of the fiber has been efiected. For most purposes, fluctuations inrroom temperature which occur from day to day efiect such minor variations in the color intensity that such fluctuations can be disregarded. However, Where exact duplication of a shade on a given fiber is desired, temperature control becomes important and should be employed, i.e., to duplicate a shade exactly the same temperature conditions, the same metal salt solution and solution and solution of the dithio-oxamide should be used.

The dithio-oxamide may be any one or a mixture of dithio-oxarnides having the formula;

. S/ in which formula R is hydrogen, alkyl, carboxyalkyl, amino-alkyl, sulfoalkyl, acetoalkyl, hydroxyalkyl, pyridyed and the particular combination of the metal ion or mixture thereof and the particular dithio-oxamide and mixture thereof. Changes in pH, concentration of either the metal ion or the dithio-oxamide and temperature alter the intensity of the color, but not the particular color itself, e.g., the application of a nickel sulfate solution and dithio-oxamide solution to silk results in blue shades, the intensity of which may be altered by using different nickel salts, or changing the concentration of either the metal salt solution or the dithio-oxamide solution applied to the silk fiber. On the other hand, the use of diiferent dithio-oxamide derivatives usually results in different colors.

As indicated, the concentration of the dithio-oxamide or mixture thereof in the solution is important in determining the intensity of the color. Concentrations may be used as low as 0.00002 Molar up to the level of a saturated solution. Preferred concentration is about 0.002 Molar which will generally produce maximum colorization in about five minutes of immersion or other treatment of fibers which have been subjected to a fiveminute treatment at room temperature with a metal ion solution having a concentration of about 0.002 M.

The dithio-oxamide and many of the derivatives hereinabove'identified are sufiiciently soluble in water so that they can be applied in the form of an aqueous solution. The higher alkyl, i.e., those having eight or more carbon atoms in thealkyl groups, and the aromatic derivatives are not sutficiently soluble in Water to be used with water as the sole solvent medium. In the case of such dithiooxarnide derivatives, a solvent mixture of water and ethanol, or water and acetone, or any other water-compatible solvent such as methanol, hexylene glycol, Cellosolve, isopropanol or Carbitol, which is capable of dis- =3 solving the dithio-oxamide derivative, is employed. In general, such solvent systems contain from 5% to 90% water, the rest being the co-solvent. Where co-solvents are utilized, color will be produced even though the solution is almost anhydrous, e.g., contains not more than 1% water. Completely anhydrous systems will not give satisfactory color formation unless the treated fiber is exposed to moisture, for example, the moisture of the air which will cause the color to appear or will improve its intensity.

The rate of reaction between the metal ion and the dithio-oxamide derivative to form the color compound increases with increase in temperature. Invariably, the metal ion adsorption rate by the fibers is slower than the reaction rate between the metal ion and the dithiooxamide derivative at any given temperature. Accordingly by applying the solution of metal ion to the fiber first and following this treatment with the treatment of a solution of dithio-oxamide or a derivative thereof, optimum coloration of the keratinous fibers is achieved. When the amount of met-a1 ion initially adsorbed is adequate, such as takes place, for example, upon immersion of the fibers for from two to ten minutes, preferably about five minutes, in an aqueous solution containing around 0.002 Molar of metal ion, color formation takes place almost instantaneously upon treatment with the dithiooxamide solution. Thus the color produced will depend upon the amount of metal ion initially adsorbed. Further exposure of the treated fiber to the dithio-oxamide solution results in no further increase in color density.

Furs, leather, and human and animal hair are dyed with substantially the same results as silk. These fibers are colored efficiently by application of the metal salt solution first at a concentration of about 0.002 Molar, followed by treatment with a solution of dithio-oxamide of substantially the same concentration.

The treatment of human hair pre-bleached with peroxides or other commonly used bleaching agents improves the color intensity obtainable by dyeing such hair in accordance with the process of this invention. Evidently, the bleaching of the hair roughens or otherwise partially damages the hair, causing it to more readily adsorb the metal ion of the metal salt solution with consequent im provement upon reaction thereof with the dithio-oxamide, or derivative thereof, to produce a more intense color, in situ. on the bleached hair.

The colors produced are reasonably fast to washing, including shampooing. Human hair, when treated first with a nickel sulfate solution followed by treatment with a solution of N,N'(2-hydroxyethyl) dithio-oxamide when shampooed with conventional shampoos, retained its original color. The colored hair was washed for periods of ten minutes, five separate times, using a concentration of the shampoo without appreciable effect upon the color.

The color imposed on the hair can be removed by treatment with a suitable oxidizing agent such as potassium permanganate, for example. Complete removal of the color, without damage to the hair or changing its original color before being dyed, is effected, for example, by the use of two solutions, namely, solution (a) KMnQ, 0.5%, potassium persulfate 1%, water 98.5% and phosphoric acid in amount to produce a pH of from 2 to 3, and solution (b) H 0 vol.) 20%, water 80% and phosphoric acid to produce a solution having a pH of 4. The dyed hair is first immersed in solution (a) for five minutes, rinsed with water and immersed in solution (b) for three minutes.

The following examples are given to illustrate the present invention. It will be appreciated that this invention is not limited to these examples.

In Examples 1 to 15, the data on which is given in Table I which follows: 30 ml. of 0.002 Molar aqueous solution of nickel sulfate at C. was mixed with 0.2 ml. of concentrated hydrochloric acid and the pH adjusted ti -by addition of monoethanolamine to about 8. A small sample of silk fabric (about /2 gram) was placed in this solution and soaked therein with intermittent mixing of the solution for about five minutes. The silk was then 5 removed from the solution and washed with tap water for about one minute and then immersed in ml. of a 0.002 Molar aqueous solution of the dithio-oxamide compound (identified in Table I) at 25 C. and allowed to soak with intermittent mixing for five minutes. The silk 10 sample was then washed for one minute with tap water and allowed to dry.

Examples 16 to 30, inclusive, were substantially the same as Examples 1 to 15, inclusive, except that nickel nitrate was substituted for nickel sulfate in each of the Examples 1 to 15, inclusive, respectively. The same colors were produced in Examples 16 to 30, inclusive, as

were produced in the respective Examples 1 to 15, in-

clusive.

Examples 31 to 45, inclusive, were substantially the same as Examples 1 to 15, inclusive, respectively, except for the substitution in each of the examples of nickel phosphate for the nickel sulfate. The same colors were produced in Examples 31 to 45, inclusive, as were produced in Examples 1 to 15, inclusive, respectively.

Examples 46 to 60, inclusive, were the same as Examples l to 15, inclusive, respectively, except that nickel 50 acetate was substituted for the nickel sulfate. Substantially the same shades were produced in the respective examples.

Examples 61 to 75, inclusive, were the same as Examples l to 15, inclusive, except that nickel chloride was 5 substituted for the nickel sulfate in the respective examples; substantially the same shades were produced in the respective examples.

In Table II, which follows, is given the data on a series of examples involving different metal ions and different dithio-oxamides identified in Table II. The method was the same as in Example 1 except that in the case of the palladium salts the pH of the solution was adjusted to within the range of from 2 to 10, namely, about 8. In the case of the copper salts, the pH was adjusted to with- 65 in the range of from 4 to 7, namely, about 5; in the case of the cobalt salts, the pH was adjusted to within the range of from 6 to 10, namely, about 8; in the case of the silver salts, the pH was adjusted to from within the range of from 2 to 9, namely, about 4; in the case of the 7 zinc salts, the pH was adjusted to from within the range of from 6 to 10, namely, about 7, and in the case of the cadmium salts the pH was adjusted to from within the range of from 6 to 10, namely, about 8. Adjustment of the pH was made by the addition of monoethanolamine, as in the case of Example 1.

arr/sear Examples Identified as Group 83 These examples were carried out substituting human hair for the silk used in the preceding examples. The colors thus obtained on the hair were substantially the same as obtained on silk, except for a minor diiference in the intensity of the color. Usually the silk had a slightly brighter color than the hair.

Examples Identified as Group 84 All of the above Examples 1 to 82, inclusive, were carried out substituting animal fur (mink) for the silk. The same colors were obtained with only a slight difierence in intensity.

Examples Identified as Group 85 Examples 1 to 82, inclusive, were repeated, using wool instead of silk in each case; substantially the same colors were obtained except for a slight difierence in intensity.

Examples Identified as Group 86 Examples 1 to 82, inclusive, were repeated, using feathers (chicken) instead of silk; substantially the same colors were obtained except for a slight difference in intensity. a

The following Table Ill gives the data on a group or examples in which the dithio-oxamide solution differed from Examples 1 to 15, inclusive, in that the solvent was 50% ethanol and 50% water. The molar concentration of the solution was 0.002. The solvent mixture of alcohol and water was used as a solvent for each of the i5. dithiooxamides employed in Examples 1 to 15, inclusive, with the production of the same color on silk in the respective duplications of Examples 1' to 15, except for the substitution of the alcohol containing solvent for the water used in Examples 1 to 15, inclusive. In Table III is given thedata on other dithio-oxamides which produced satisfactory color on silk using anethanol-water solvent system; the dithio-oxarnides identified in Table III when employed in water alone yielded poor color values.

In the next group of examples, the solvent system for the dithio-oxamide compound was a mixture of acetone andwater containing 50% of acetone. This solvent system, when used with the dithio-oxamide compounds of each of Examples 1 to 1-5, inclusive, resulted in substantially the same color in each case. In'Table IV which follows is given the data on other dithio-oxamide compounds which, when applied in a solvent system containing acetone in water, resulted in good dyeings whereas when applied from a solution containing only water gave poorer dyeings.

TABLE IV Exlarrnple Metal Salt Dithio Compound Color 93 Nickel Sulfate... N,N-Bis(5 carbox- Dark Purple.

yamybdithio oxamide. 94 .do N,N-Bis(8-earboxy- Light Yellow.

propyDclithio-oxamido. 95 .110 N,N-D ilfurfuryl-d.ithio Pink.

osami e. 96 "do N,NDiisopropyl- Light Orange,

,dithio-oxamide. 97 .110 N,N-Bis(p-chloro Light Pink,

bonzyDdithio-oxamide. 98 d0 N,N-Bis(o-chloro- Do.

benzylldithiooxamide. 99 ..do.. N,N'-Bis(oarbethoxy, Coral.

methybdishiooxamide. 100 .d0. N,N'-Bis(3-pyridyl- Pink.

methyDdi-thio-oramlde. 101 0 N,N'-Bis(phenyl p'yri- Yellow.

dyl-mgthylmithiooxami e. 102 do N,N'-Bis(2-pyrldyl- Do.

, methybdithiooxamlde. 103 N,N-Bis(m-methyl- Light Pink.

benzybdithiooxamide. N,N'-Di:lodecyl dithio- Light Orangeoxamide. Pink. N,N-Dieyclohexyl Light Orange.

dlthio-oxamide. do. N,N-Dibenzyldithlo-' Purple.

oxamide.

Example 107 This example differs from Example 1 in that the nickel sulfate solution was replaced by a solution prepared by mixing 96 parts of aqueous cadmium sulfate (0.002 Molar) with four parts of aqueous nickel sulfate (0.002 Molar). A rose pink color was obtained.

Example 108 This example differs from Example 1 in that the dithiooxamide solution employed in Example 1 was replaced by a solution prepared by mixing four parts of an aqueous solution of dithio-oxamide (0.002 Molar) with 96 parts of an aqueous solution of N,N-(carboxyethyl) dithiooxamide. The silk was dyed a gray color.

Example 109 This example diiiers from Example I in thatthe dithiooxamide solution was replaced by a 0.002 Molar solution of N,N'-bis(2-acetoxycthyl) dithio-oxarnide and the nickel sulfate solution was replaced by a mixture of 50 parts of nickel sulfate (0.002 Molar) and 50 parts of copper sulfate (0.002 Molar). The silk was dyed a chocolate brown.

The above dyeings when tested for wash-fastness were found to withstand several rigorous washings, including washing with Water containing soap, and/or synthetic detergents without appreciable loss of color.

it will be noted that the present invention provides a novel process of dyeing keratinous fibers, resulting in dyeings of desired shade, reasonably fast to washing and which in the preferred embodiments involves use of very small amounts of color-producing material, the amounts being so small as not to aiiect the hand or feel of the fiber.

In this specification, unless otherwise indicated, the percentage values are on a weight basis.

Since certain changes in carrying out the process of dyeing keratinous fibers and in the resultant dyed fibers, whether as individual fiber, yarn or fabric form may be made without departing from the scope of this invention. it is intended that all matter contained in this description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: V

1. A process of dyeing keratinous fibers which comprises, soaking the fibers in an aqueous solution of a metal salt from the group consisting of the phosphates, nitrates, acetates, chlorides, sulfates and citrates of cobalt, nickel, copper, zinc, palladium, silver and cadmium at a temperature of from 20 to 95 C., removing the keratinous fibers from contact with said solution of metal salt and then soaking the thus treated fibers in a solution of a dithio-oxamide selected from the group consisting of (a) dithio-oxamides having the formula:

C-NHR S 10 salt is a copper salt and the solution applied to the fibers has a pH of from 4 to 6.

4. The method as defined in claim 1, in which the metal salt is a cobalt salt and the solution applied to the fibers has a pH of from 6 to 10.

5. The method of dyeing fibers defined in claim 1, in which the concentration of the metal salt solution is from 0.00002 Molar up to the level of saturation of the solution and the concentration of the dithio-oxamide solution is from 0.00002 Molar up to the level of saturation of the dithio-oxamide in said solution.

6. The process of dyeing keratinous fibers defined in claim 1, in which the concentration of the dithio-oxamide solution is approximately 0.002 Molar.

7. The process of dyeing keratinous fibers defined in claim 1, in which the concentration of the metal salt solution is about 0.00002 Molar and the concentration of the dithio-oxamide solution 0.002 Molar.

OTHER REFERENCES Chem. Abstracts, 1947, 3208-3209. Chem. Abstracts, 1955, 5213. Chem. Abstracts, vol. 50, 1956, 4358. 

1. A PROCESS OF DYEING KERATINOUS FIBERS WHICH COMPRISES, SOAKING THE FIBERS IN AN AQUEOUS SOLUTION OF A METAL SALT FROM THE GROUP CONSISTING OF THE PHOSPHATES, NITRATES, ACETATES, CHLORIDES, SURFATES AND CIRTATES OF COBALT, NICKEL, COPPER, ZINC, PALLADIUM, SILVER AND CADIUM AT A TEMPERATURE OF FROM 20* TO 95*C., REMOVING THE KERATINOUS FIBERS FROM CONTACT WITH SAID SOLUTION OF METAL SALT AND THEN SOAKING THE THUS TREATED FIBERS IN A SOLUTION OF A DITHIO-OXAMIDE SELECTED FROM THE GROUP CONSISTING OF (A) DITHIO-OXAMIDES HAVING THE FORMULA: 